A student measures the mass of a metal bar as 57.21 g. the student fills a graduated cylinder with water and determines the volume of water to be 53.70 mL. The student places the metal bar into the graduated cylinder and records the new volume as 58.80 mL. Calculate the density of the metal bar.

The density of the metal bar is 11.217 g / ml.

Explanation:

The density of the metal bar can be found by using the ratio of mass and volume.

Given,

The weight of the metal bar is 57.21 g.

The Volume of water is 53.70 ml.

The Volume of the water and the bar is 58.80 ml.

The volume of the metal bar is 58.80 - 53.70 = 5.10 ml.

                  Density = mass / volume

                                = 57.21 / 5.1 = 11.217 g / ml.

The density of the metal bar is about 11.2 g / ml.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.